de Marne: Mice squeeze into house through tiny holes

Jun. 20, 2012

Written by

Henri de Marne

Q: I am having trouble with mice. I have looked everywhere but cannot figure out how they get in the house. I see some small openings around where the electric cable goes into the house at the basement level, but it seems too small to let them in. Iíd appreciate any suggestions you have. -- Williston, Vt.

A: Mice can get through holes as small as a quarter-inch. Their fur makes them look larger than they are.

The small space you have identified is a likely point of entry. There are probably others around the foundation, such as an outside garden hose bibb, the holes where a gas pipe or oil filler and breather pipes enter the house, etc. Small spaces where the foundation meets the first-floor framing are also possible entries; these can often be caulked.

A great product is available for sealing small spaces that are nonetheless too large to be caulked: the Xcluder Rodent & Pest Barrier. It comes in a kit that includes a stainless steel/poly-fiber mesh mat, several strips of the same material, a pair of blunt-nosed scissors for cutting and pushing the Xcluder into small spaces, and a pair of neoprene gloves to be worn when cutting the mesh to the right size to avoid getting slivers of steel in your skin.

The Xcluder is made in the United States, an important point in this age of outsourcing, and can be purchased online at www.buyxcluder.com for less than $10. The kit also has instructions for effective installation and some interesting facts about rodents, which carry diseases and cause deadly fires by chewing on electrical wires. This information should convince those who find mice cute that they are dangerous pests.

Q: I emailed you a few weeks ago thinking I had silverfish. After looking up silverfish and firebrats on the Internet, I realized that is not what I have. These insects are brown on top and have a grayish underbody. They seem to like moist places and come out at night. The adult size is about 1 / 2inch long. Do you have any idea what these are and how I might get rid of them? -- via email

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A: Sorry, but I canít identify these critters with so little information and without a photo. I suggest that you catch one, put it in a small plastic bag and take it to a local pest control operator or the entomology department of your local extension service.

Q: I read your column in the Chicago area Daily Herald and enjoy all the useful information it provides.

I live in a house in northern Illinois. The property is surrounded by wetlands and ferns. A constant influx of water comes through our drain tiles and into the sump pump due to a high water table or spring nearby. Our sump pump has done an excellent job of keeping our basement dry.

My question is, what is the proper level to set the sump pump to turn on? My sump pump begins pumping after 6 inches of water has entered the pit, resulting in frequent on/off cycles. My neighbor has his sump set up so the water in the sump pit levels off at a certain point and the drain tile leading into the pit ends up being half submerged, resulting in much less frequent on/off cycles. I am assuming that it levels off at this point because that is the height of the water table.

Which set-up is correct and why? I have a Zoeller submersible primary pump with an Aquanot AC/DC backup. -- via email

A: There is no set rule. Your submersible Zoeller pump has a float that triggers the pump, and it is possible to adjust it on certain models. You can call Zoellerís technical service at 800-928-7867 and follow the prompts, or email the company at webmaster zoeller.com to find out if the float on your model can be adjusted. If it canít, and if you want it to come on less frequently, you can set it up on a couple of bricks.

Henri de Marneís book, ďAbout the House,Ē is available at www.upperaccess.com and in bookstores. His website is www.henridemarne.com. Readers can send questions to Henri de Marneís email address at henridemarne gmavt.net, or to First Aid for the Ailing House, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.